Evaporator for refrigerators



Sept. 20, 1932.

G. w. MASON EVAPORATOR FOR REFRIGERATORS Filed April 11, 1929 65a. W/WHSON INVENTOR ATTORNEY Patented Sept. 20, 1932 UNITED STATES PATENT OFFICE GEORGE W. MASON, OF DETROIT, MICHIGAN, ASSIGNOR TO KELVINATOR CORPORATION, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN EVAPORATOR FOR REFRIGERATORS Application filed April 11,

This invention relates to artificial refrigeration apparatus; and, it has particular relation to apparatus of the above named character, which shall be specially applicable in '5 refrigeration cabinets for domestic use.

An object of'the invention is to provide an. apparatus in which water, or food products of any character whatever, can be inserted in the apparatus in a metaillic or other suitable tray, and frozen in a relatively short time.

Another object of the invention is to provide an apparatus in which the operation of a condensing unit of a refrigeration apparatus will be controlled automatically in response to the temperature of substances contained in a freezing tray adapted to be inserted in an evaporating unit employed in such apparatus.

Another object of the invention is to provide a refrigeration apparatus in which the operation of the condensing unit thereof, will be initiated automatically upon the disposition of a warm freezing tray in thermal contact with the evaporating unit.

Another object of the invention is to provide a refrigeration apparatus in which a section of an evaporating conduit embodied in a refrigerant evaporating unit, will be disposed in good thermal contact with a freezing tray, thus providing for the absorption of heat from the latter by an evaporatng conduit section, at a relatively rapid rate.

Another object of the invention is to provide a refrigerant evaporating unit embodying an expansion conduit having an end portion in thermal contact with a freezing tray,

to which end portion, a thermostat for initiating the operation of a refrigerant expansion unit, is directly attached.

Another object of the invention is to provide a refrigerant evaporating unit in which substances of various character can be" reduced very quickly to a frozen state, without materially affecting the normal temperature 3 of such refrigeration apparatus in regions where substances are not required to be frozen.

Prior to the invention it has been the practice to employ refrigerant fluid evaporating nunits of a size or capacity capable of main 1929. Serial R... 354,349.

there, often for several hours, before the substances would become entirely frozen. By reason of the fact that such evaporating units were constructed primarily for the purpose of cooling a relatively large space to a predetermined low temperature, it was necessary, in order to decrease the freezing time, to change entirely the range of operation of the apparatus, as a result of which a large amount of unnecessary work was done in cooling the entire refrigerator cabinet to a temperature lower than that whichnormally was required. Consequently, it was thought to be the better practice simply to provide a refrigerant evaporating unit of such size and capacity as to efliciently cool the larger portion of a refrigerator cabinet and to permit 75 the freezing of substances therein at any rate at which such an apparatus might be capable of performing this office.

This invention comprehends the employment of a structure which is capable of operating efliciently in a refrigerator cabinet, both as a cooling unit under normal condition of operation; and, under special circumn stances, when it is particularly desirable to employ it as a freezing unit, to perform this function at a relatively rapid rate without materially afiecting the temperature of a refrigerator cabinet in which the apparatus is employed.

The automatic operation of the structure embodying the invention is provided for by employing a control apparatus of any suitable character for causing the operation of the expansion unit and thus removing'heat from a freezing tray whenever a tray containing a warm substance required to be frozen is inserted in the particular ortion of the evaporating unit employed or this purpose. Such evaporating unit will operate continuously'thereafter, until the sublot erties.

the expansion conduit which are aflected by substances having temperatures only slightly greater than the latter.

For a better understanding of the invention, reference may now be had to the accompanying drawing, forming a part of this specification, in which:

Figure 1 1s a fragmentary cross-sectional view of a refrigerator cabinet provided with an evaporating unit embodying the principles of the invention;

Figure 2 is a longitudinal cross-sectional view of the evaporating unit embodied in the structure illustrated by Figure 1;

Figure 3 is a diagrammatical view illustrating a form of refrigerant condensing unit which may be incorporated in a structure embodying the invention.

A refrigerant evaporating unit 10 employed in practising the invention is secured rigidly, in any suitable manner (not shown), in the upper portion of-a refrigerating cabinet Which is designated generally by the numeral 11.

A tank 12 constructed of sheet metal, or other suitable material having good heat conductive properties, is provided with a filler cap 13 through which a brine solution, or other substance having good heat retaining properties, may be introduced. A sleeve portion 14, of the brine tank 10, projects interiorly thereof to provide a horizontally disposed aperture for the reception of a freezing tray 16. This tray is adapted to be su ported by a thin metallic plate 17 composed of sheet copper or other suitable material having good heat conductive prop- The plate, in turn, is supported upon the upper surface of the bottom of the sleeve 14 It is specially desirable to provide a very large number of points of contact between the tray and the plate 17, and the plate 17 is preferably soldered to the bottom of the sleeve 14, in order to ensure an efficient conduction of heat through such metallic members. If the tray 16 is provided with a smooth planular bottom surface, then the sleeve 14 should have a similar smooth surface to contact therewith.

, One end of the plate 17 projects outwardly beyond the end of the sleeve 14 and is curved sharply to provide a downwardly extending loop 18 in the lower end of which an eye 19, for receiving a bulb 20 of a thermostat 25, is formed. The parallel portions of the loop 18 above the eye 19 are provided with aligned openings 21 through which a threaded portion 22 of a coupling 23 projects. A nut 24, adapted to be associated operatively With the threaded portion 22, is employed for the purpose of clamping the parallel portions of the loop 18 rigidly against a shoulder 26, formed intermediate the end of the coupling 23, thus retaining the bulb 20 of the thermostat 25 within the eye 19. The threaded portion 22 of the coupling 23 also is adapted to receive internally thereof an end portion of a suction line 27 communicating With the compressor 35 of a refrigerant condensing unit 30. The end of the coupling 23 opposite the threaded portion 22 is adapted to be secured rigidly in an opening formed in the tank 12 by soldering or other suitable means capable of providing a good thermal contact between the coupling and the tank.

A sinuous section 28 of an evaporating conduit 29 is secured in the end of the coupling 23 projecting within the tank 12, thus communicating through the interior of the coupling with the suction line 27. The conduit 28 is adapted to be soldered, as indicated at 15, throughout substantially its entire length to the inner surface of the bottom of the sleeve 14. It is apparent that the thermal contact between the section 28 of the expansion conduit 29, and the freezing tray 16, will be of a very eflicient character.

While the conduit 28 has been illustrated as being of the sinuous formation, it is to be understood that it may be curved in any other suitable manner so long as substantially the entire conduit is disposed in good thermal contact with the bottom of the sleeve.

The opposite end of the conduit 28 is connected by a bent portion 31, with one end of a helically wound or other suitably curved section 32 comprising the remaining portion of the expansion conduit 29. The opposite end of the conduit 32 is connected through a, coupling 33 with an expansion valve 34. The latter is secured rigidly to a boss 36 formed on the coupling 33, which, in turn, is secured rigidly to the brine tank 12. A conduit 37 connects the expansion valve 34 with the high side of the refrigerant compressor 35.

In the operation of the invention, when the tray 16, containing a warm substance of any character desired to be frozen, is inserted in the sleeve 14, the bottom of the tray immediately warms the plate 17. The bulb 20 of the thermostat 25, being in good thermal contact with the plate 17 by reason of its being secured rigidly in an extension of the-latter, is warmed sufiiciently to cause its operation for from the tray 16 at a very rapid rate, by reason of the excellent thermal contact therewith, the refrigerant liquid is evaporated therein at a rate almost as great as the rate at which the gasified liquid iswithdrawn by the refrigerant compressor through the suction line 27. Hence, the temperature of the substance in the tray 16 will be reduced at a very rapid rate and will be substantially frozen before any liquid reaches the coupling 23 in an unevaporated state. If any substantial amount of liquid does reach the coupling 23 before the substance in the tray 16 is entirely frozen, its expansion in the warm coupling will reduce the temperature of the thermostat bulb 20, soon thereafter, to a degree suificient to cause the operation of the thermostat to break the electrical circuit through the motor and thus discontinue the operation of the apparatus. However, the heat in the unfrozen substance will quickly increase the temperature of the thermostat bulb 20 by reason of thegood metallic contact between the tray 14 and the bulb 20 through the metallic extension of the plate 17 in which the bulb is secured. This increase in the temperature of the bulb will again cause the operation of the thermostat to close the circuit through the motor by which the apparatus is operated and another cycle of operation will follow. Thus it will be seen that, in the event-the liquid is not entirely frozen in the first cycles of operation of the apparatus, such cycles of operation will be repeated at short intervals until such time as the substance in the tray 16 is entirely frozen. When this condition occurs it is apparent that the plate 17 will not continue to conduct a substantial amount of heat from the bottom of the tray to the bulb of the thermostat and, consequently, the

cycles of operation of the apparatus will be controlled only by tempetature ofother objects and fluid by which the. thermostat bulb is affected. Hence, after the substance in the tray is frozen, the apparatus will be operated in exactly the same manner as though the thermostat bu-lb were not in direct metallic contact with the bottom of the tray.

It is to be understoodthat this invention is not limited to an apparatus in which a brine tank is employed as a special heat retaining medium. Any other substances, such as cast iron, aluminum, brass, earthenware or bituminous materials, may be employed instead of a brine tank if desired or such heat retaining mediums may be dispensed with entirely. Likewise, the invention is not limited to any particular type of refrigeration apparatus or to the use of evaporating conduits as distinguished from any of the other known structures for providing space in which the evaporation of a fluid is adapted to occur.

Although, the specification discloses only the preferred form of this invention, and describes in detail but a single application thereof, it will be apparent to those skilled in the art that the invention is not so limited, but

that various modifications and changes may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

I claim:

1. A refrigerant evaporating unit comprising a curved liquid refrigerant evaporating conduit disposed throughout substantially its entire length in uniform thermal contact with a bottom portion of a freezing tray, a thermostat for controlling the periods of operation of the evaporating unit, and a metallic attachment connecting the thermostat with the freezing tray to provide for the conduction of heat therebetween.

2. A refrigerant evaporating unit comprising a brine tank having a horizontally disposed sleeve projecting therein, a refrigerant evaporating conduit of curved formation disposed in heat conducting relation to the bottom of such sleeve, a thermostat disposed externally of the sleeve for causing intermittent periods of operation ofthe evaporating unit, and a metallic member projecting between the sleeve and the thermostat for providing thermal contact therebetween.

3. A refrigerant evaporating unit comprising a brine tank having a metallic sleeve projecting internally thereof; a refrigerant evaporating conduit having a brine cooling section disposed within the tank, and a sleeve cooling section soldered to the bottom of the aforesaid sleeve; and a metallic plate project'- ing externally of the sleeve in thermal contact with the bottom portion thereof and a thermostat secured adjacent the extremity of the plate.

4. A refrigerant evaporating unit compris ing a brine tank having a metallic sleeve projecting internally thereof; a refrigerant evaporating conduit having a brine cooling section disposed within the tank, and a sleeve cooling section soldered to the bottom of the aforesaid sleeve; and a metallic plate projecting externally of the sleeve in thermal contact with the bottom portion thereof to which a thermostat, and an end portion of the refrigerant evaporating conduit, is secured.

V 5. A refrigeration apparatus comprising a compartment suitable for the circulation of cooling fluid internally thereof, a refrigerant evaporator having a horizontally disposed port-ion, a thermostat disposed externally of the evaporator in the path of the circulating fluid in said compartment, and a metallic plate in intimate thermal contact with a temperature responsive portion of said thermostat and projecting along the upper surface of the horizontal portion of the evaporator for supporting a freezing tray thereon.

6. A refrigerating apparatus comprising a refrigerating compartment for the circulation of air internally thereof, an apertured refrigerant evaporating unit disposed in such compartment for cooling the circulating air therein, a thermostat disposed externally of said evaporating unit in the path of the circulating air in said compartment, and a metallic member projecting into the aperture in the evaporating unit for supporting a freezing tray therein and extending from the aperture externally of the evaporator and in thermal contact With the aforesaid thermostat.

7. A refrigerating apparatus comprising a refrigerating compartment for the circulation of air internally thereof, an apertured' refrigerant evaporating unit arranged in said compartment, said evaporating unit comprising a vaporized refrigerant suction conduit projecting externally thereof, a thermostat disposed externally of said evaporating unit and in the path of the circulating air in the interior of the compartment, and a metallic plate for supporting a freezing tray in the interiorof the evaporating unit, said plate being disposed in thermal contact With the lower portion of the aforesaid aperture, the thermostat, and the conduit.

In testimony whereof I hereunto aflix my signature.

. GEORGE W. MASON. 

